The present disclosure relates to subject matter contained in Japanese Patent Application No. 9-296784 (filed on Oct. 29, 1997), Japanese Patent Application No. 9-306710 (filed on Nov. 10, 1997), and Japanese Patent Application No. 10-207293 (filed on Jul. 23, 1998), which are expressly incorporated herein by reference in their entireties.
1. Field of the Invention
The present invention relates to a drainage tube introducer for an endoscope that is used through an instrument-inserting channel of the endoscope to introduce a drainage tube into a body cavity for the purpose of draining (through-draining) a narrow part in the body cavity.
2. Description of the Prior Art
To draw accumulated pancreatic juice from the pancreas or the pancreatic duct into the stomach, there is a technique whereby a drainage tube is introduced into the patient's body through an endoscope. According to the conventional procedure, a puncturing instrument that has a guide wire removably inserted therein is passed through an instrument-inserting channel of an endoscope (particularly, an ultrasonic endoscope), and the pancreas is pierced with the puncturing instrument from the inner wall of the stomach.
Thereafter, with the distal end of the guide wire left in the pancreatic duct, the puncturing instrument is drawn out of the patient's body. Then, a drainage tube is inserted into the pancreatic duct by passing it over the guide wire. Finally, the guide wire is drawn out of the patient's body, thereby allowing the drainage tube to be left under the conditions that one end of the drainage tube opens into the pancreatic duct, and the other end opens into the stomach.
A conventional puncturing instrument used in the above-described procedure has an inner tube that allows a guide wire to be removably inserted therein over the entire length of the inner tube. The inner tube has a tubular needle at the distal end thereof. The tubular needle has a syringe needle-like shape. The inner tube is axially movably inserted in a sheath that is removably inserted into an instrument-inserting channel of an endo scope.
As stated above, introduction of a drainage tube through an endoscope requires a troublesome operation in which after the tissue in a body cavity has been punctured, the puncturing instrument is drawn out, with the distal end of the guide wire left in the pancreatic duct. Then, the drainage tube is inserted into the pancreatic duct by passing it over the guide wire. In particular, it is very difficult and troublesome to draw out only the puncturing instrument by an operation conducted at the proximal end of the sheath while preventing the distal end of the guide wire from dislodging from the pancreatic duct.